<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="../css/bootstrap.css">
    <script src="../js/jq-1.12.4.js"></script>
    <script src="../js/bootstrap.js"></script>
    <style>
        #app {
            width: 100px;
            height: 100px;
            background-color: brown;
            transition: all 3s;
        }

        #app:hover {
            background-color: blue;
        }
    </style>
</head>

<body>
    <div id="app"></div>
</body>
<script>
    $(function () {
        //改变成原生js对象
        let app = $('#app')[0]
        app.addEventListener('transitionend', function (e) {
            console.log(e);
            alert('过渡效果执行结束')
        })
    })
</script>

</html>